Erica andevalensis and Erica australis growing in the same extreme environments: Phytostabilization potential of mining areas

Mining activities in the abandoned Sao Domingos mine (Portugal, Iberian Pyrite Belt, IPB) generated a large amount of sulphide-rich waste rocks and tailings. Erica andevalensis Cabezudo and Rivera and Erica australis L plants grow spontaneously in contaminated sites that have high concentrations of potentially hazardous elements, high acidity and nutrient deficiency. The aim of this paper was to analyse the behaviour of monospecific and mixed communities of both Erica species in these extreme environments in order to evaluate their potential for phytostabilization of soils and mining wastes. Metal and metalloids were analysed in the soils (total and available fraction) and in the roots and above-ground biomass of the plants, and these values were then used to estimate uptake, tolerance, translocation and accumulation in the plants. The plants showed a high content of trace elements in the roots and above-ground biomass. In fact, the content of chemical elements in the aerial parts was higher than the range considered as normal for Al and Fe, and exceeded the toxic values for As, Mn and Pb. These values were superior to those found in the available soil fraction for these elements, and even superior to the soil total content for Mn. The lack of phytotoxicity symptoms suggests that Erica plants can be considered as a Mn-accumulator and acid-, Al-, As-, Fe- and Mn-tolerant. Furthermore, both E. andevalensis and E. australis were found to form a large biomass in monospecific and mixed communities on both wet acid sulphate soils/sediments in riverbanks and dry mine tailings and contaminated soils. Hence, both Erica species can be considered suitable for phytostabilization of metal(loid)-polluted sites in abandoned mining districts of the IPB. (C) 2014 Elsevier B.V. All rights reserved.